在多个页面中重复使用相同的方法

Question

I have a method

public void CheckLogin()
{
    if ((Session["UserName"] == "") || (Session["UserName"] == null))
    {
        Response.Redirect("Account/Login.aspx");
    }
}

I dont want rewrite it in every page. How can I define this one time and call this function in other pages?

Answer 1

You generally put this in a utilities class. Mark the function as static. Put the utilities class in the App_Code folder (make this folder in the root of your site if you don't have one). Make sure your class has the appropriate using statements.

using System;
using System.Web;

public class AuthenticationUtilities
    {
    public static void CheckLogin()
        {
        if (HttpContext.Current.Session["UserName"]==null || HttpContext.Current.Session["UserName"]=="")
            {
            HttpContext.Current.Response.Redirect("Account/Login.aspx");
            }
        }
    }

Then you call it from your pages like this...

AuthenticationUtilities.CheckLogin();

By the way, you're reinventing the wheel. You should be using a technology such as Identity instead of rolling your own. I'm only providing this answer in case you need to at another point create a function common to various pages.

Answer 2

Use inheritance to provide common functionality to your web pages.

Create a page that performs the common task and then derive all your other pages from that page.

public class MyPage : MyBasePage

Using this approach, there's no need to explicitly call anything. It will all be handled in the base class, which you could then extend as needed. All you need to remember is to change your class declaration so it inherits from your base class.

Another approach might be to stick this in a common master page. But I don't like that approach as much.

Answer 3

If you are doing such an authorization check, you probably want to handle the authorization event. This is common enough that there is a built-in way to do it:

From User-based Authorization ...

Step 1: Defining URL Authorization Rules in Web.config

Step 2: Fixing the Workflow for Unauthorized, Authenticated User

Answer 4

create a class file with a static class may be called "SessionCheck.cs"

and write this function in it as Static

public Static void CheckLogin()

    {

        if ((Session["UserName"] == "") || (Session["UserName"] == null))
        {

            Response.Redirect("Account/Login.aspx");

        }

    }

then you can access it from any page like

SessionCheck.CheckLogin();

Answer 5

Put it in a Session Helper class.

public class SessionHelper
{
    public static void CheckLogin()
    {
        if ((Session["UserName"] == "") || (Session["UserName"] == null))
        {
            Response.Redirect("Account/Login.aspx");
        }
    }
}

Then you call it like so.

SessionHelper.CheckLogin();

Answer 6

create a class file who extend from Page,

public class Navegable: Page

so in the init function put your code

void NavigablePage_PreInit(object sender, EventArgs e)
        {
if ((Session["UserName"] == "") || (Session["UserName"] == null))
        {
            Response.Redirect("Account/Login.aspx");
        }
}

so, the web form extend from navegable.

MyPage : Navegable

thats is, all your webform who extend from navegable will run the validation